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1 | /* |
2 | * Copyright (C) 2004 IBM Corporation |
3 | * |
4 | * Author: Serge Hallyn <serue@us.ibm.com> |
5 | * |
6 | * This program is free software; you can redistribute it and/or |
7 | * modify it under the terms of the GNU General Public License as |
8 | * published by the Free Software Foundation, version 2 of the |
9 | * License. |
10 | */ |
11 | |
12 | #include <linux/export.h> |
13 | #include <linux/uts.h> |
14 | #include <linux/utsname.h> |
15 | #include <linux/err.h> |
16 | #include <linux/slab.h> |
17 | #include <linux/user_namespace.h> |
18 | #include <linux/proc_ns.h> |
19 | |
20 | static struct uts_namespace *create_uts_ns(void) |
21 | { |
22 | struct uts_namespace *uts_ns; |
23 | |
24 | uts_ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL); |
25 | if (uts_ns) |
26 | kref_init(&uts_ns->kref); |
27 | return uts_ns; |
28 | } |
29 | |
30 | /* |
31 | * Clone a new ns copying an original utsname, setting refcount to 1 |
32 | * @old_ns: namespace to clone |
33 | * Return ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise |
34 | */ |
35 | static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns, |
36 | struct uts_namespace *old_ns) |
37 | { |
38 | struct uts_namespace *ns; |
39 | int err; |
40 | |
41 | ns = create_uts_ns(); |
42 | if (!ns) |
43 | return ERR_PTR(-ENOMEM); |
44 | |
45 | err = proc_alloc_inum(&ns->proc_inum); |
46 | if (err) { |
47 | kfree(ns); |
48 | return ERR_PTR(err); |
49 | } |
50 | |
51 | down_read(&uts_sem); |
52 | memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); |
53 | ns->user_ns = get_user_ns(user_ns); |
54 | up_read(&uts_sem); |
55 | return ns; |
56 | } |
57 | |
58 | /* |
59 | * Copy task tsk's utsname namespace, or clone it if flags |
60 | * specifies CLONE_NEWUTS. In latter case, changes to the |
61 | * utsname of this process won't be seen by parent, and vice |
62 | * versa. |
63 | */ |
64 | struct uts_namespace *copy_utsname(unsigned long flags, |
65 | struct user_namespace *user_ns, struct uts_namespace *old_ns) |
66 | { |
67 | struct uts_namespace *new_ns; |
68 | |
69 | BUG_ON(!old_ns); |
70 | get_uts_ns(old_ns); |
71 | |
72 | if (!(flags & CLONE_NEWUTS)) |
73 | return old_ns; |
74 | |
75 | new_ns = clone_uts_ns(user_ns, old_ns); |
76 | |
77 | put_uts_ns(old_ns); |
78 | return new_ns; |
79 | } |
80 | |
81 | void free_uts_ns(struct kref *kref) |
82 | { |
83 | struct uts_namespace *ns; |
84 | |
85 | ns = container_of(kref, struct uts_namespace, kref); |
86 | put_user_ns(ns->user_ns); |
87 | proc_free_inum(ns->proc_inum); |
88 | kfree(ns); |
89 | } |
90 | |
91 | static void *utsns_get(struct task_struct *task) |
92 | { |
93 | struct uts_namespace *ns = NULL; |
94 | struct nsproxy *nsproxy; |
95 | |
96 | rcu_read_lock(); |
97 | nsproxy = task_nsproxy(task); |
98 | if (nsproxy) { |
99 | ns = nsproxy->uts_ns; |
100 | get_uts_ns(ns); |
101 | } |
102 | rcu_read_unlock(); |
103 | |
104 | return ns; |
105 | } |
106 | |
107 | static void utsns_put(void *ns) |
108 | { |
109 | put_uts_ns(ns); |
110 | } |
111 | |
112 | static int utsns_install(struct nsproxy *nsproxy, void *new) |
113 | { |
114 | struct uts_namespace *ns = new; |
115 | |
116 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
117 | !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) |
118 | return -EPERM; |
119 | |
120 | get_uts_ns(ns); |
121 | put_uts_ns(nsproxy->uts_ns); |
122 | nsproxy->uts_ns = ns; |
123 | return 0; |
124 | } |
125 | |
126 | static unsigned int utsns_inum(void *vp) |
127 | { |
128 | struct uts_namespace *ns = vp; |
129 | |
130 | return ns->proc_inum; |
131 | } |
132 | |
133 | const struct proc_ns_operations utsns_operations = { |
134 | .name = "uts", |
135 | .type = CLONE_NEWUTS, |
136 | .get = utsns_get, |
137 | .put = utsns_put, |
138 | .install = utsns_install, |
139 | .inum = utsns_inum, |
140 | }; |
141 |
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v2.6.34-rc5
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